6. The Western Roman Empire
After ruling much of Europe for centuries, the Western Roman Empire suddenly collapsed in 476 CE. Waves of barbarian invasions—combined with crippling economic troubles and relentless political infighting—brought the mighty empire to its knees almost overnight. The fall of Rome stunned the ancient world and ushered in the so-called Dark Ages, marking a turning point in European history. The suddenness of this collapse reminds us how even the most enduring powers can vanish in a moment of crisis. Learn more at History Extra.
